A roofing product needs a means for attaching the roofing to the surface to be covered, a strengthening layer to maintain the integrity of the roofing layer and an upper surface to be in contact with the environment to minimize the exposure of the layers below.
It is well recognized that the ultraviolet rays from the sun are most destructive to exposed asphalt surfaces.
Applications of coal-tar and asphalt layers as part of a sheet of roofing must be shielded from the sunlight to increase the useful life of the roofing. The ultraviolet light tends to polymerize the hydrocarbon molecules and harden the surface which results in cracking of the asphalt and leaks in the roof. Conventional ways of shielding the asphalt layer is with crushed rock or gravel, flakes of aluminum, aluminum paint, etc.
Examples of two attempts to solve the roofing problem are illustrated in U.S. Pat. Nos. (Jackson) 3,770,559 and (Hurst) 3,900,102.
The Jackson patent discloses a plurality of layers having an aluminum foil sheet bonded to a bituminous adhesive re-enforced with a nylon-fabric.
The Hurst patent discloses a surface coating material for masonry surfaces which includes a fabric impregnated with a bitumen mixture.